arXiv subjects

Natalia Costas

Publications and source records attributed to Natalia Costas.

4 recordsLinked to original sources

arXiv2026

Interconnecting Regional QKD Networks: Hybrid Key Delivery Across Quantum Domains

QKD technology is being increasingly adopted inside the network core for protecting information transport against any form of computational attacks. However, the use of QKD for wide-area internetworking is still challenging and costly, due to its strong trust assumptions and the low achievable key rates in long QKD links. This paper presents a standards-driven design and implementation of a unified hybrid key delivery service for a network of isolated QKD domains (subnetworks using QKD as provider technology for secret key generation) connected via classical WAN links. The framework follows a distributed architecture and uses a hybrid approach where keys generated in a domain are securely relayed to other domains with PQC (Kyber), dynamically routed, and managed at the system level. The solution has been implemented in an operational testbed comprising three regional subnetworks. We present the design principles, the deployment, and the experimental performance results for this scalable key delivery service.

cs.NI↗

arXiv2025

Benchmarking Distributed Quantum Computing Emulators

Scalable quantum computing requires architectural solutions beyond monolithic processors. Distributed quantum computing (DQC) addresses this challenge by interconnecting smaller quantum nodes through quantum communication protocols, enabling collaborative computation. While several experimental and theoretical proposals for DQC exist, emulator platforms are essential tools for exploring their feasibility under realistic conditions. In this work, we introduce a benchmarking framework to evaluate DQC emulators using a distributed implementation of the inverse Quantum Fourier Transform ($\mathrm{QFT}^{\dagger}$) as a representative test case, which enables efficient phase recovery from pre-encoded Fourier states. The QFT is partitioned across nodes using teleportation-based protocols, and performance is analyzed in terms of execution time, memory usage, and fidelity with respect to a monolithic baseline. As part of this work, we review a broad range of emulators, identifying their capabilities and limitations for programming distributed quantum algorithms. Many platforms either lacked support for teleportation protocols or required complex workarounds. Consequently, we select and benchmark four representative emulators: Qiskit Aer, SquidASM, Interlin-q, and SQUANCH. They differ significantly in their support for discrete-event simulation, quantum networking, noise modeling, and parallel execution. Our results highlight the trade-offs between architectural fidelity and simulation scalability, providing a foundation for future emulator development and the validation of distributed quantum protocols. This framework can be extended to support additional algorithms and emulators.

quant-ph↗

arXiv2025

Continuous-variable spatio-spectral quantum networks in nonlinear photonic lattices

Multiplexing information in different degrees of freedom and use of integrated and fiber-optic components are natural solutions to the scalability bottleneck in optical quantum communications and computing. However, for bulk-optics systems, where size, cost, stability, and reliability are factors, this remains either impractical or highly challenging to implement. In this paper we present a framework to engineer continuous-variable entanglement produced through nondegenerate spontaneous parametric down-conversion in χ^(2) nonlinear photonic lattices in spatial and spectral degrees of freedom that can solve the scalability challenge. We show how spatio-spectral pump shaping produce cluster states that are naturally distributable in quantum communication networks and a resource for measurement-based quantum computing.

quant-ph↗

arXiv2024

Review of Distributed Quantum Computing. From single QPU to High Performance Quantum Computing

The emerging field of quantum computing has shown it might change how we process information by using the unique principles of quantum mechanics. As researchers continue to push the boundaries of quantum technologies to unprecedented levels, distributed quantum computing raises as an obvious path to explore with the aim of boosting the computational power of current quantum systems. This paper presents a comprehensive survey of the current state of the art in the distributed quantum computing field, exploring its foundational principles, landscape of achievements, challenges, and promising directions for further research. From quantum communication protocols to entanglement-based distributed algorithms, each aspect contributes to the mosaic of distributed quantum computing, making it an attractive approach to address the limitations of classical computing. Our objective is to provide an exhaustive overview for experienced researchers and field newcomers.

quant-ph↗